Changes In Concentration Of Oxygenated Hemoglobin Research Articles

Effects of footbaths on prefrontal cortex activity and autonomic nervous function: A randomized controlled crossover trial

Objective: Footbaths are employed in nursing practice in East Asian countries. Assessing the effects of footbaths based on the findings of multiple physiological responses is relevant to ensuring evidence-based nursing practice. This study aimed to investigate the effects of thermal stimulation by a footbath on prefrontal cortex activity and autonomic nervous function. Methods: This study was a randomized controlled crossover trial conducted on healthy participants from a college student population. Each participant underwent a footbath in warm water and a control condition for 10 min on two different days. The order of the two treatments was randomized. The oxygenated hemoglobin concentration in the prefrontal cortex, laterality scores of the oxygenated hemoglobin concentration changes, and autonomic responses were evaluated. Results: A total of 17 healthy participants were recruited. A footbath in warm water significantly reduced both the prefrontal cortex and sympathetic nerve activities 7 min after the start of the footbath compared with the control condition. Moreover, a footbath in warm water tended to activate the left prefrontal cortex rather than the right prefrontal cortex. Conclusions: The changes in the prefrontal cortex activity and autonomic nervous function were associated with the relaxing effect of the thermal stimulation by the footbath. Furthermore, this effect was highest at 7 min after the start of the footbath. This study has the potential to contribute to the evidence-based use of footbaths. Trial Registration: UMIN-CTR Clinical Trial: UMIN000033735

Executive control of freestyle skiing aerials athletes in different training conditions.

IntroductionDue to the actual limitation of training conditions, the freestyle skiing aerials winter training term is short. Training tasks such as adaptability training and developing new skills are needed in summer training. When facing different training environments, freestyle skiing aerial athletes’ executive control over their abilities could be affected, which can affect their performance. Therefore, we want to research the effect of training conditions on executive control in freestyle skiing aerials athletes and its neural mechanism.Materials and methodsThirty-two freestyle skiing aerials athletes were recruited. We evaluated their executive control and used fNIRS to measure oxygenated hemoglobin concentration changes in the prefrontal cortex during a rapid event-related design go/nogo task with different training condition-activated materials.ResultsAthletes’ behavior control in the summer condition has a lower accuracy than it is in the control condition. Athletes’ behavior control in the summer and winter training conditions had a longer reaction time than that in the control condition. The activation of the bilateral dlPFC and orbitofrontal cortex had a significant main effect across training conditions when freestyle skiing aerial athletes completed executive control tasks. The activation of athletes’ bilateral vlPFC and left dlPFC had an interaction between training conditions and behavioral control.ConclusionDifferent training conditions can lead to freestyle skiing aerial athletes executive control ability to drop, players in different training conditions show less activation on both sides of the vlPFC and orbitofrontal. The bilateral vlPFC and left dlPFC have an integrated effect on behavior inhibition across training conditions.

A study of dynamic hand orthosis combined with unilateral task-oriented training in subacute stroke: A functional near-infrared spectroscopy case series.

BackgroundMotor dysfunction in the upper extremities after stroke prohibits people with stroke from being independent in daily living. The application of fNIRS to explore brain activity under rehabilitation intervention is a research focus on neurorehabilitation.ObjectiveThe purpose of this study was to explore, using a grip-release ring motor task, the activated changes of regions of interest and changes in motor function utilizing fNIRS technology and test scales on persons with stroke who received unilateral task-oriented therapy with a hand orthosis in the early subacute stroke period before and after intervention. The study aimed to find a sensitive motor task and region of interest first, then to evaluate the feasibility and mechanism of this rehabilitation method by utilizing fNIRS technology in the next randomized controlled trial.MethodsIn this case series, eight right-handed, right hemiplegia subacute stroke persons (6 males,2 females from age 47 to 72) were enrolled. They received 30 min of unilateral task-oriented therapy without orthosis and 30 min of unilateral task-oriented therapy with orthosis (5 days/week) for 4 weeks. Activated channel numbers and beta values based on oxygenated hemoglobin concentration change using a grip-release ring motor task were estimated with fNIRS. Clinical outcome measures, including grip strength evaluation, action research arm test, and Fugl-Meyer assessment of the arm, were evaluated at the same time.ResultsIndividual activation analysis showed that, after intervention, Subjects 1, 2, 6, 7, and 8 had the maximum mean beta value located in the left premotor cortex, while Subjects 4 and 5 had the maximum mean beta value located in the left sensorimotor cortex. The activation analysis of Subject 3 showed the maximum mean beta value located in the right premotor cortex. Deactivations of left sensorimotor cortex, left premotor cortex, and bilateral prefrontal cortex were observed after intervention which were different from other cases. Group activation analysis showed that bilateral cerebral hemispheres were activated in all eight participants, with right hemisphere and right supplementary motor cortex activated dominantly. After the intervention, the activation of bilateral hemispheres decreased but in different brain regions; there was a trend that the activation intensity of left sensorimotor cortex, right premotor cortex, and right prefrontal cortex decreased while activation intensity of left premotor cortex and left prefrontal cortex increased. Each participant demonstrated improvements in all the clinical test scales after intervention.ConclusionsLeft premotor cortex, left sensorimotor cortex, and right supplementary motor cortex may be the primary regions of interest. Grasp-release ring task was not appropriate to achieve our fNIRS research objective and a more sensitive motor task or more sensitive evaluating indicator should be used in further studies.

Feasibility of fNIRS in Children with Developmental Coordination Disorder

IntroductionBalance deficits are heterogeneous among children with Developmental Coordination Disorder (DCD). Balance performance depends on different balance domains, each associated with specific underlying neurological systems. In DCD, any of these domains can be affected, but the control mechanisms are poorly understood. The mirror neuron system (MNS) seems to play a key-role in DCD-related deficits. To understand the role of MNS as a control mechanism underlying the balance deficits, simultaneous registration of cortical MNS activity while performing balance tasks is imperative. Therefore, a protocol for combining real-time registration of cortical MNS activity during functional balance tasks in children with DCD, CP and TD is introduced. Methods: Children with DCD, CP and TD (n=108) aged 5-10yr perform preselected tasks of the Kids-BESTest, representing specific balance domains (mixed design): leaning with eyes closed (stability limits/verticality), single-leg-stance, alternate stair touching (anticipatory balance), in-place response, compensatory stepping backward (reactive balance) and walking over obstacles (gait stability). Simultaneously, functional Near-Infrared Spectroscopy (fNIRS) monitors cortical activity involving the MNS: premotor, inferior and superior parietal cortex and supplementary motor area. An 8-8-optode bundle, making 22 channels, targets this region of interest. Outcome measures are: (de)oxygenated hemoglobin concentration changes per task per channel. Results: In this ongoing research, the protocol was already feasible in 19 children (7.52±1.19). Conclusion: Simultaneous registration of cortical MNS activity (fNIRS) and Kids-BESTest scores will help increase the understanding of the control mechanisms underlying the heterogeneous balance problems in DCD. Consequently, first steps are made to confirm whether DCD shows deviant or delayed development.DisclosureNo significant relationships.

Synaptosomal-Associated Protein 25 Gene Polymorphisms Affect Treatment Efficiency of Methylphenidate in Children With Attention-Deficit Hyperactivity Disorder: An fNIRS Study.

Methylphenidate (MPH) is the first-line drug for the treatment of children with attention-deficit hyperactivity disorder (ADHD); however, individual curative effects of MPH vary. Many studies have demonstrated that synaptosomal-associated protein 25 (SNAP-25) gene MnlI polymorphisms may be related to the efficacy of MPH. However, the association between SNAP-25MnlI polymorphisms and changes in brain hemodynamic responses after MPH treatment is still unclear. This study used functional near-infrared spectroscopy (fNIRS) to preliminarily investigate the interaction of MPH treatment-related prefrontal inhibitory functional changes with the genotype status of the SNAP-25 gene in children with ADHD. In total, 38 children with ADHD aged 6.76–12.08 years were enrolled in this study and divided into the following two groups based on SNAP-25 gene MnlI polymorphisms: T/T genotype group (wild-type group, 27 children) and G allele carrier group (mutation group, 11 children). The averaged oxygenated hemoglobin concentration changes [Δavg oxy-Hb] and deoxyhemoglobin concentration changes [Δavg deoxy-Hb] in the frontal cortex before MPH treatment and after 1.5 h (post-MPH1.5h) and 4 weeks (post-MPH4w) of MPH treatments were monitored using fNIRS during the go/no-go task. SNAP-IV scores were evaluated both pre-MPH and post-MPH4w treatments. In the T/T genotype group, [Δavg oxy-Hb] in the dorsolateral prefrontal cortex was significantly higher after 4 weeks of MPH (post-MPH4W) treatment than pre-treatment; however, in the G allele group, no significant differences in [Δavg oxy-Hb] were observed between pre- and post-treatments. In the go/no-go task, the accuracy was significantly increased post-MPH4w treatment in the T/T genotype group, while no significant differences were observed in response time and accuracy of the “go” sand no-go task in the G allele group for pre-MPH, post-MPH1.5h, and post-MPH4w treatments. The T/T genotype group exhibited a significant decrease in SNAP-IV scores after MPH treatment, while the G allele group showed no significant difference. In conclusion, fNIRS data combined with SNAP-25 MnlI polymorphism analysis may be a useful biomarker for evaluating the effects of MPH in children with ADHD.

Syntactic and Semantic Processing in Japanese Sentence Reading: A Research Using Functional Near-Infrared Spectroscopy (fNIRS).

In order to examine whether syntactic processing is a necessary prerequisite for semantic integration in Japanese, cortical activation was monitored while participants engaged in silent reading task. Congruous sentences (CON), semantic violation sentences (V-SEM), and syntactic violation sentences (V-SYN) were presented in the experiment. The participants' oxygenated hemoglobin concentration changes during the reading task were measured using functional near-infrared spectroscopy. The results suggest that the CON sentences did not require additional cognitive load on syntactic processing or semantic processing. The V-SEM sentences demanded great cognitive load on semantic processing. Besides, it also elicited great cognitive load on syntactic processing. The V-SYN sentences induced great cognitive load on syntactic processing, but it did not induce additional load on semantic processing. These evidence demonstrates that, in Japanese language processing, the difficultness of semantic processing could influence the difficultness of syntactic processing, while the difficultness of syntactic processing would not influence the difficultness of semantic processing. Our findings are suggestive of the possibility that in Japanese language reading, semantic processing precedes syntactic processing, or semantic processing and syntactic processing are in parallel.

Rhythmic Change of Cortical Hemodynamic Signals Associated with Ongoing Nociception in Awake and Anesthetized Individuals: An Exploratory Functional Near Infrared Spectroscopy Study.

Patients undergoing surgical procedures are vulnerable to repetitive evoked or ongoing nociceptive barrage. Using functional near infrared spectroscopy, the authors aimed to evaluate the cortical hemodynamic signal power changes during ongoing nociception in healthy awake volunteers and in surgical patients under general anesthesia. The authors hypothesized that ongoing nociception to heat or surgical trauma would induce reductions in the power of cortical low-frequency hemodynamic oscillations in a similar manner as previously reported using functional magnetic resonance imaging for ongoing pain. Cortical hemodynamic signals during noxious stimuli from the fontopolar cortex were evaluated in two groups: group 1, a healthy/conscious group (n = 15, all males) where ongoing noxious and innocuous heat stimulus was induced by a contact thermode to the dorsum of left hand; and group 2, a patient/unconscious group (n = 13, 3 males) receiving general anesthesia undergoing knee surgery. The fractional power of low-frequency hemodynamic signals was compared across stimulation conditions in the healthy awake group, and between patients who received standard anesthesia and those who received standard anesthesia with additional regional nerve block. A reduction of the total fractional power in both groups-specifically, a decrease in the slow-5 frequency band (0.01 to 0.027 Hz) of oxygenated hemoglobin concentration changes over the frontopolar cortex-was observed during ongoing noxious stimuli in the healthy awake group (paired t test, P = 0.017; effect size, 0.70), and during invasive procedures in the surgery group (paired t test, P = 0.003; effect size, 2.16). The reduction was partially reversed in patients who received a regional nerve block that likely diminished afferent nociceptive activity (two-sample t test, P = 0.002; effect size, 2.34). These results suggest common power changes in slow-wave cortical hemodynamic oscillations during ongoing nociceptive processing in conscious and unconscious states. The observed signal may potentially promote future development of a surrogate signal to assess ongoing nociception under general anesthesia.

Relationship between the Difference in Oxygenated Hemoglobin Concentration Changes in the Left and Right Prefrontal Cortex and Cognitive Function during Moderate-Intensity Aerobic Exercise

Previous studies have indicated that changes in oxygenated hemoglobin concentration (O2Hb) in the prefrontal cortex (PFC) are associated with changes in cognitive function. Therefore, the present study aimed to explore the effect of differences in O2Hb levels in the left and right PFC (L-PFC and R-PFC, respectively) on cognitive function after exercise. This study included 12 healthy male college students. The exercise regimen consisted of 4 min of warm-up and rest each, followed by 20 min of moderate-intensity exercise and 20 min of post-exercise rest. Participants underwent the 2-back cognitive test thrice (pre-exercise, post-exercise, and after the 20 min post-exercise rest period), and their reaction times were recorded. O2Hb levels in the PFC were monitored using functional near-infrared spectroscopy. We analyzed the correlations between changes in post-exercise reaction times and differences in peak O2Hb levels (L-PFC minus R-PFC), area under the curve for O2Hb changes, and increases in the O2Hb slope during exercise. Peak O2Hb, area under the curve (AUC) for O2Hb change, and increase in the slope of O2Hb were significantly correlated with changes in reaction time. These findings provide insight into the mechanism by which O2Hb differences between the L-PFC and R-PFC affect cognitive function.

Cerebral hemodynamics predicts the cortical area and coding scheme in the human brain for force generation by wrist muscles

The goal of this study is to identify the cortical area maximally active over the primary sensorimotor cortex (SM1) and characterize the cortical encoding for force production by wrist muscles in the human brain. The technique of functional near-infrared spectroscopy (fNIRS) was used to continuously monitor the changes in hemoglobin concentrations from the left hemisphere during isometric contractions of wrist flexion muscles over a broad range of load forces (0 ∼ 8 kgf) on the right hand. As previously shown in primate studies, this action produced hemodynamic activity predominantly in the wrist area localized dorsally to the finger region over SM1 and the hemodynamic response was systematically related to the level of load intensity. The coding scheme for force production in terms of hemodynamic signals was characterized defining eight trajectory parameters (four for amplitude coding and four for temporal coding) and analyzed for the area maximally activated over SM1. The trajectory parameter representing the oxygenated hemoglobin concentration change at the end of motor task (amplitude coding) and the timing of maximum change in oxygenated hemoglobin concentration (temporal coding) was most strongly correlated with the load variation in a superliner manner. All these results indicate the applicability of fNIRS to monitor and decode cortical activity that is correlated with low-level motor control such as isometric muscle contractions. This study may provide not only insights into cortical neural control of muscle force but also predictors of muscle force in clinical diagnostics and neural interfaces for the human brain.

Design of a wearable four-channel near-infrared spectroscopy system for the measurement of brain hemodynamic responses.

Objectives This work describes the design and development of a four-channel near-infrared spectroscopy system to detect the oxygenated and deoxygenated hemoglobin concentration changes in the brain during various motor tasks. Methods The system uses light-emitting diodes corresponding to two wavelengths of 760nm and 850nm sensitive to deoxygenated and oxygenated hemoglobin concentration changes, respectively. The response is detected using a photodetector with an integrated transimpedance amplifier. The system is designed with four channels for functional near-infrared spectroscopy (fNIRS) signals acquisition. Two experiments were conducted to demonstrate the ability of the system to detect the changes in hemodynamic responses of different tasks. In the first experiment, the hemodynamic changes during motor execution and imagery of right- and left-fist clenching tasks were acquired by the developed system and validated against a standard multichannel NIRS system. In another experiment, the fNIRS signals during rest and motor execution of right-fist clenching task were acquired using the system and classified. Results The results demonstrate the ability of the designed system to detect the brain hemodynamic changes during various tasks. Also, the activation patterns obtained by the developed system with a minimum number of channels are on par with those obtained by the commercial system. Conclusions The developed four-channel NIRS system is user-friendly and has been designed with inexpensive components, unlike the commercially available NIRS instruments that are cumbersome and expensive.

Working Memory of Patients with Mild Cognitive Impairment due to Brain Trauma Based on fNIRS.

Objective To discuss the activation characteristics of the prefrontal cortex of people with mild cognitive impairment （MCI） due to brain trauma during working memory tasks. Methods The psychological experiment design software E-prime was used and N-back paradigm was adopted as working memory task. Functional near-infrared spectroscopy （fNIRS） was used to detect changes in cortical oxygenated hemoglobin concentrations of 22 channels within the prefrontal lobe of 24 people with MCI due to brain trauma （study group） and 27 healthy volunteers （control group） with matching gender and age. Behavioral data, such as the number of keystroke errors and reaction time, were recorded simultaneously. Independent samples t test and non-parametric test were used to compare the mean value of oxygenated hemoglobin concentration change, the number of key errors and the mean value of reaction time of the two groups in each task. Results （1） The differences in the number of errors and reaction time between the two groups in 1-back and 2-back tasks had statistical significance （P<0.05）.The main effects of task load and group were both significant （task F=14.11, P=0.001 1; group F=10.39, P=0.001 5）. （2） During the 1-back task, the differences in oxygenated hemoglobin concentration changes of the 22 channels between the two groups had no statistical significance （P>0.05）. During the 2-back task, the differences in oxygenated hemoglobin concentration changes of the two groups in channel 2, 3, 7, 9, 10, 11, 14, 15, 18, 19, 21 and 22 had statistical significance （P<0.05）. （3） In the 1-back task, the left frontal pole and dorsolateral prefrontal area in both groups were activated. In the 2-back task, the activation areas of the control group were the left frontal pole area and the left dorsolateral prefrontal area, while that of the study group almost covered most of the left and right frontal pole areas, which were scattered and the right area was activated, too. Conclusion Patients with MCI due to brain trauma have obvious working memory impairment, and during the 2-back working memory task, the activation of the prefrontal lobe decreased, but the activation range was wider.

Moderate-Intensity Aerobic Exercise Restores Appetite and Prefrontal Brain Activity to Images of Food Among Persons Dependent on Methamphetamine: A Functional Near-Infrared Spectroscopy Study.

The brain prefrontal control system is critical to successful recovery from substance use disorders, and the prefrontal cortex (PFC) regulates striatal reward-related processes. Substance-dependent individuals exhibit an increased response to drug rewards and decreased response to natural, nondrug rewards. Short-term aerobic exercise can ameliorate craving and inhibitory deficits in methamphetamine users, but the effect of exercise on food reward is unknown. This study used functional near-infrared spectroscopy (fNIRS) to measure the effects of moderate- and high-intensity short-term aerobic exercise on prefrontal activity related to food images and recorded the subjective feelings of appetite in methamphetamine-dependent users. In total, 56 men who met the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria for methamphetamine dependence, with a mean (SD) body mass index of 24.7 (3.5) kg/m2 and age of 30.2 (5.1) years, were randomly assigned to one of two exercise groups: moderate intensity (n = 28; 65%–75% of maximum heart rate) and high intensity (n = 28; 76%–85% of heart rate maximum). Each group also performed a resting control session for 35 min 1 week before or after the exercise, in a counterbalanced order. Mean oxygenated hemoglobin concentration changes in the PFC when viewing visual food cues were assessed by fNIRS, and subjective feelings of appetite were self-rated using visual analog scales after moderate- or high-intensity aerobic exercise and after the resting control session. A continuous-wave NIRS device was used to obtain functional data: eight sources and seven detectors were placed on the scalp covering the PFC, resulting in 20 channels per participant. We found that moderate-intensity aerobic exercise significantly increased both, the activation of the left orbitofrontal cortex (OFC) to images of high-calorie food (P = 0.02) and subjective sensations of hunger (F(1,54) = 7.16, P = 0.01). To our knowledge, this study provides the first evidence that moderate-intensity aerobic exercise increases OFC activity associated with high-calorie food images and stimulates appetite in methamphetamine-dependent individuals. These changes suggest that exercise may reestablish the food reward pathway hijacked by drugs and restore sensitivity to natural rewards. This evidence may contribute to the development of specific exercise programs for populations with methamphetamine dependence.

Altered near-infrared spectroscopy response to breath-holding in patients with fibromyalgia.

Fibromyalgia (FM) is a complex syndrome characterized by chronic widespread pain and a heightened response to pressure. Most medical researches pointed out that FM patients with endothelial dysfunction and arterial stiffness. A continuous-wave near-infrared spectroscopy (NIRS) system is used in present study to measure the hemodynamic changes elicited by breath-holding task in patients with FM. Each patient completed a questionnaire survey including demographics, characteristics of body pain, associated symptoms, headache profiles and Hospital Anxiety and Depression Scale. A total of 27 FM patients and 26 health controls were enrolled. In comparison with healthy controls, patients with FM showed lower maximal and averaged change of oxyhemoglobin concentration in both the left (1.634 ±0.890 and 0.810 ±0.525 μM) and the right (1.576 ±0.897 and 0.811 ±0.601 μM) prefrontal cortex than healthy controls (P < .05 for both sides) during the breath-holding task. In conclusion, FM is associated with altered cerebrovascular reactivity measured by NIRS and breath-holding task, which may reflect endothelial dysfunction or arterial stiffness. Oxygenated hemoglobin concentration changes of healthy controls and FM patients.

Characteristics of oxygenated hemoglobin concentration change during pleasant and unpleasant image-recall tasks in patients with depression: Comparison with healthy subjects.

Patients with major depressive disorder (MDD) have been reported to show cognitive impairment in attention, cognition control, and motivation. The prefrontal cortex plays an important role in the pathophysiology of depression. Neurophysiological abnormalities have been examined in MDD patients by several neuroimaging studies. However, the underlying neural mechanism is still unclear. We evaluated brain function during pleasant and unpleasant image-recall tasks using multichannel near-infrared spectroscopy (NIRS) in MDD patients. The subjects were 25 MDD patients and 25 age- and sex-matched healthy controls. Patients were classified according to DSM-IV-TR criteria. We measured the oxygenated hemoglobin concentration change (δoxyHb) in the forehead and temporal lobe during image-recall task with pleasant (e.g., puppy) and unpleasant (e.g., snake) images using NIRS. To check whether all subjects understood the task, they were asked to draw pictures of both image tasks after NIRS measurement. The δoxyHb in the healthy group was significantly higher than that in the MDD group in the bilateral frontal region during the unpleasant condition. A significant negative correlation between the Hamilton Rating Scale for Depression score and δoxyHb was observed in the left frontal region during the unpleasant condition. We suggest that image-recall tasks related to emotion measured by NIRS might be a visually useful psychophysiological marker to understand the decrease in the frontal lobe function in MDD patients. In particular, we suggest that the decrease in δoxyHb in the left frontal lobe is related to the severity of depression.

Measuring speaker\u2013listener neural coupling with functional near infrared spectroscopy

The present study investigates brain-to-brain coupling, defined as inter-subject correlations in the hemodynamic response, during natural verbal communication. We used functional near-infrared spectroscopy (fNIRS) to record brain activity of 3 speakers telling stories and 15 listeners comprehending audio recordings of these stories. Listeners’ brain activity was significantly correlated with speakers’ with a delay. This between-brain correlation disappeared when verbal communication failed. We further compared the fNIRS and functional Magnetic Resonance Imaging (fMRI) recordings of listeners comprehending the same story and found a significant relationship between the fNIRS oxygenated-hemoglobin concentration changes and the fMRI BOLD in brain areas associated with speech comprehension. This correlation between fNIRS and fMRI was only present when data from the same story were compared between the two modalities and vanished when data from different stories were compared; this cross-modality consistency further highlights the reliability of the spatiotemporal brain activation pattern as a measure of story comprehension. Our findings suggest that fNIRS can be used for investigating brain-to-brain coupling during verbal communication in natural settings.

Central command generated prior to arbitrary motor execution induces muscle vasodilatation at the beginning of dynamic exercise.

The purpose of this study was to examine the role of central command, generated prior to arbitrary motor execution, in cardiovascular and muscle blood flow regulation during exercise. Thirty two subjects performed 30 s of two-legged cycling or 1 min of one-legged cycling (66 ± 4% and 35% of the maximal exercise intensity, respectively), which was started arbitrarily or abruptly by a verbal cue (arbitrary vs. cued start). We measured the cardiovascular variables during both exercises and the relative changes in oxygenated-hemoglobin concentration (Oxy-Hb) of noncontracting vastus lateralis muscles as index of tissue blood flow and femoral blood flow to nonexercising leg during one-legged cycling. Two-legged cycling with arbitrary start caused a decrease in total peripheral resistance (TPR), which was smaller during the exercise with cued start. The greater reduction of TPR with arbitrary start was also recognized at the beginning of one-legged cycling. Oxy-Hb of noncontracting muscle increased by 3.6 ± 1% (P < 0.05) during one-legged cycling with arbitrary start, whereas such increase in Oxy-Hb was absent with cued start. The increases in femoral blood flow and vascular conductance of nonexercising leg were evident (P < 0.05) at 10 s from the onset of one-legged cycling with arbitrary start, whereas those were smaller or absent with cued start. It is likely that when voluntary exercise is started arbitrarily, central command is generated prior to motor execution and then contributes to muscle vasodilatation at the beginning of exercise. Such centrally induced muscle vasodilatation may be weakened and/or masked in the case of exercise with cued start.

Changes in Cerebral Hemodynamics during Complex Motor Learning by Character Entry into Touch-Screen Terminals.

IntroductionStudies of cerebral hemodynamics during motor learning have mostly focused on neurorehabilitation interventions and their effectiveness. However, only a few imaging studies of motor learning and the underlying complex cognitive processes have been performed.MethodsWe measured cerebral hemodynamics using near-infrared spectroscopy (NIRS) in relation to acquisition patterns of motor skills in healthy subjects using character entry into a touch-screen terminal. Twenty healthy, right-handed subjects who had no previous experience with character entry using a touch-screen terminal participated in this study. They were asked to enter the characters of a randomly formed Japanese syllabary into the touch-screen terminal. All subjects performed the task with their right thumb for 15 s alternating with 25 s of rest for 30 repetitions. Performance was calculated by subtracting the number of incorrect answers from the number of correct answers, and gains in motor skills were evaluated according to the changes in performance across cycles. Behavioral and oxygenated hemoglobin concentration changes across task cycles were analyzed using Spearman’s rank correlations.ResultsPerformance correlated positively with task cycle, thus confirming motor learning. Hemodynamic activation over the left sensorimotor cortex (SMC) showed a positive correlation with task cycle, whereas activations over the right prefrontal cortex (PFC) and supplementary motor area (SMA) showed negative correlations.ConclusionsWe suggest that increases in finger momentum with motor learning are reflected in the activity of the left SMC. We further speculate that the right PFC and SMA were activated during the early phases of motor learning, and that this activity was attenuated with learning progress.

Blunted brain activation in patients with schizophrenia in response to emotional cognitive inhibition: A functional near-infrared spectroscopy study

IntroductionPatients with schizophrenia (SZ) have deficits of facial emotion processing and cognitive inhibition, but the brain pathophysiology underlying these deficits and their interaction are not clearly understood. We tested brain activity during an emotional face go/no-go task that requires rapid executive control affected by emotional stimuli in patients with SZ using functional near-infrared spectroscopy (fNIRS). MethodsTwenty-five patients with SZ and 28 healthy control subjects were studied. We evaluated behavioral performance and used fNIRS to measure oxygenated hemoglobin concentration changes in fronto-temporal areas during the emotional go/no-go task with emotional and non-emotional blocks. ResultsPatients with SZ made more errors and had longer reaction times in both test blocks compared with healthy subjects. Significantly greater activation in the inferior, superior, middle, and orbital frontal regions were observed in healthy subjects during the emotional go/no-go block compared to the non-emotional go/no-go block, but this difference was not observed in patients with SZ. Relative to healthy subjects, patients with SZ showed less activation in the superior and orbital frontal and middle temporal regions during the emotional go/no-go block. DiscussionOur results suggest that fronto-temporal dysfunction in patients with SZ is due to an interaction between abnormal processing of emotional facial expressions with negative valence and cognitive inhibition, especially during the rapid selection of rule-based associations that override automatic emotional response tendencies. They indicate that fronto-temporal dysfunction is involved in the pathophysiology of emotional–cognitive deficits in patients with SZ.

Prefrontal activation during inhibitory control measured by near-infrared spectroscopy for differentiating between autism spectrum disorders and attention deficit hyperactivity disorder in adults

The differential diagnosis of autism spectrum disorders (ASDs) and attention deficit hyperactivity disorder (ADHD) based solely on symptomatic and behavioral assessments can be difficult, even for experts. Thus, the development of a neuroimaging marker that differentiates ASDs from ADHD would be an important contribution to this field. We assessed the differences in prefrontal activation between adults with ASDs and ADHD using an entirely non-invasive and portable neuroimaging tool, near-infrared spectroscopy. This study included 21 drug-naïve adults with ASDs, 19 drug-naïve adults with ADHD, and 21 healthy subjects matched for age, sex, and IQ. Oxygenated hemoglobin concentration changes in the prefrontal cortex were assessed during a stop signal task and a verbal fluency task. During the stop signal task, compared to the control group, the ASDs group exhibited lower activation in a broad prefrontal area, whereas the ADHD group showed underactivation of the right premotor area, right presupplementary motor area, and bilateral dorsolateral prefrontal cortices. Significant differences were observed in the left ventrolateral prefrontal cortex between the ASDs and ADHD groups during the stop signal task. The leave-one-out cross-validation method using mean oxygenated hemoglobin changes yielded a classification accuracy of 81.4% during inhibitory control. These results were task specific, as the brain activation pattern observed during the verbal fluency task did not differentiate the ASDs and ADHD groups significantly. This study therefore provides evidence of a difference in left ventrolateral prefrontal activation during inhibitory control between adults with ASDs and ADHD. Thus, near-infrared spectroscopy may be useful as an auxiliary tool for the differential diagnosis of such developmental disorders.

Reduced brain activation during imitation and observation of others in children with pervasive developmental disorder: a pilot study.

BackgroundChildren with pervasive developmental disorder (PDD) are thought to have poor imitation abilities. Recently, this characteristic has been suggested to reflect impairments in mirror neuron systems (MNS). We used near-infrared spectroscopy (NIRS) to examine the brain activity of children with PDD during tasks involving imitation and observations of others.FindingsThe subjects were 6 male children with PDD (8–14 years old) and 6 age- and gender-matched normal subjects (9–13 years old). A video in which a woman was opening and closing a bottle cap was used as a stimulus. Hemoglobin concentration changes around the posterior part of the inferior frontal gyrus and the adjacent ventral premotor cortex were measured with a 24-channel NIRS machine during action observation and action imitation tasks. Regional oxygenated hemoglobin concentration changes were significantly smaller in the PDD group than in the control group. Moreover, these differences were clearer in the action observation task than in the action imitation task.ConclusionsDysfunction in the MNS in children with PDD was suggested by the reduced activation in key MNS regions during tasks involving observations and imitations of others. These preliminary results suggest that further studies are needed to verify MNS dysfunction in children with PDD.